YOU SAID:
I've got a massive erection
INTO JAPANESE
私は大規模な勃起があります
BACK INTO ENGLISH
I have a large erection
INTO JAPANESE
大きな勃起があります
BACK INTO ENGLISH
I have a big erection
INTO JAPANESE
私は大きな勃起があります
BACK INTO ENGLISH
I have a big erection
That didn't even make that much sense in English.